Abstract C044: Inter-ethnic differential gene expression in stage II recurrent colorectal cancers

Abstract

Abstract Inter-ethnic differential gene expression in stage II recurrent colorectal cancers Prachi Bajpai1, Amr Elholy1, Michael Behring1, Dongquan Chen2, 3, Kevin Hale1, Sumit Agrawal1, Hyung-Gyoon Kim1, Trafina Jadhav1, Temegsen Samuel4, Upender Manne1, 3 1Department of Pathology, 2Division of Preventive Medicine, Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA, 3O’Neal Comprehensive Cancer Center of UAB, Birmingham; 4Department of Pathobiology, College of Veterinary Medicine, Tuskegee University, Tuskegee, Alabama, USA Background and Objective: For colorectal cancer (CRC), the second most common cause of cancer-related death in the US, there are racial/ethnic disparities in incidence and mortality. Of these patients, 25-35% with pathologic Stage II CRCs exhibit recurrence after surgery with curative intent. Relative to Caucasian (CA) patients, African American (AA) patients with CRC have a 20% higher stage-specific mortality. The present study delineates a distinct gene expression profile, specific for Stage II CRCs, based on disease recurrence and patient race/ethnicity. Methods: We obtained gene expression profiles for Stage II CRCs from 16 AA and 30 CA patients by the use of Affymetrix GeneChip microarrays. Samples from patients with recurrent disease, within 5 years post-surgery, were compared to those with non-recurrent CRCs within 5 years post-surgery. For comparison between AA with CA patients, gene expression was assessed. Results: For recurrent CRCs, there were nine genes common to AA and CA patients, suggesting a common gene signature specific for Stage II disease. For tumors, relative to their corresponding normal tissues, there was higher expression of five of these genes; the direction of association with disease recurrence was distinct with race/ethnicity. GFM2, DCAF17, and GEN1 had a positive association with recurrence in CAs and a negative association with recurrence in AAs. Additionally, for recurrent patients, TAPBP and FEZ were upregulated in AAs and downregulated in CAs (False Discovery Rate <0.05 for all genes). BCL2L2, OXA1L, AHNAK2, and MEGF6 were consistently overexpressed in CRCs of both race/ethnicity groups. Currently, we are validating these findings in a prospective Stage II CRC cohort to correlate observations with time to recurrence. Conclusion: The present study identifies molecular signatures, specific for Stage II CRCs, for patients of two ethnic backgrounds, and contribute to a better understanding of the CRC health disparities for AAs and CA. This work was supported by a NIH/NCI grant (U54CA118948). Citation Format: Prachi Bajpai, Amr Elholy, Michael Behring, Dongquan Chen, Kevin Hale, Sumit Agrawal, Hyung-Gyoon Kim, Trafina Jadhav, Temegsen Samuel, Upender Manne. Inter-ethnic differential gene expression in stage II recurrent colorectal cancers [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C044.